Latch tripping mechanism



Jan. 11, 1949. H. 'w. SANFORD ,7

I LATCH TRIPPING MECHANISM- Filed March l4, 1944 3 Shee tsSheet 1 w {IIIIIIII J,

Jan. 11, 1949. w, SANFORD LATCH TRIPPING MECHANISM Filed March 14, 1944 3 Sheets-Sheet 2 H. w. SANFORD LATCH TRIPPING MECHANISM Jan. 11, 1949.

-- 5 Shets-Sheefl 3 Filed March 14, 1 944 Patented Jan. 11, 1949 LATCH TRIPPING MECHANISM Hugh W. Sanford, Knoxville, Tenn, assignor to The: Sanford Investment Company, Wilmington; Del;, a corporation of Delaware Appli'cationMarch' 14, 1944; Serial No. 526,426

I IZ'CIEimS;

tween therails of the car in position to engage an actuating portionof" the latch means, to release the latch means for dischargingthe lad; ing from the" can Theremay be conditions underwhich it would be impracticable tolocate the tripping mechanism between the rails and to move it therefrom up to apoint where it would engage the latch actuating means-to release the door for dropping.

It is the object of this invention to provide for: the location of the tripping mechanism outside of the-track rails, but in a secure'protected position, where the latch actuating means would not bein danger of striking abutments in the mine, even in'tlieevent of derailment.

character such as to form a relatively fixed abut-- ment for thelatch actuating means; or it may move'up to an'actuatin'gposition' where it will engage the actuating meansto-cause a; releasing-- of the doorsfor dropping'when the car reaches its dumping posit-ion.

According to the-preferred embodiments of-the' invention, the major portion of" the tripping means is protected preferably behind a portion of the end structure of" the car, such as a laterally projecting plate thereon connected either with the end wall or with the end sill structure,

sothat obstructions that might be encountered in the mine even during normal operation" or" in the event ofderailment, will not engage the actuating means of the latch mechanism to trip the latch and release the door; nor-will such ob-- structions cause'injury thereto. This protecting means would prevent a lump of coal, for instance, that may have: dropped intothe track, from contacting the actuatlngportion of the latch means.

It is also preferable that the latch orlatches that support the door, be mounted on a transverse-shaft that extends-through a side portion of the-car at a point which:would nevertheless In this position, thetripping mechanism may be of abe protected by the flare plate of the side por-' tion and terminates in a protected position inwardly of the vertical plane'of the lateral edge of the flare plate at the point where it extends out farther, but cariying an actuating cam or other means ata point outside the car side wall imposition to be engaged by a tripping abutment to release the latch or latches when the car reaches its dumping position.

The latchactuating member or cam member thatismounted on the projecting portion of the latch supporting shaft, is in position to be engaged by an abutment at the dumping point. This-abutment may be relatively fixed in an upstanding position beside the track where it will act through a narrow notch in the end wall structure and strike the tripping cam and release the doors-for dropping; or provision may be made for elevating the abutment from a lowered positionto a tripping position in the path of the cam member. In either event, the tripping mechanism: is located relatively close beside the track rails and will engage the actuating camthat is connected with the latch at a point loeated'in a protected position on the car.

The invention is shown in different embodiments in the accompanying drawings inwhich:

Fig. 1 is a side elevation of a mine car and track, showingone form of latch tripping mechanism;

Fig. 2 is an enlarged side elevation of the latch end of the car, showing the tripping mechanism partly in section;

Fig. 3 is a partial longitudinal sectional view therethrough, with parts in elevation;

Fig. in a partial end elevationof the ear;

Fig. 5 is a side elevation of a portion of the car'sh'owing another form of tripping mechanism; and

Fig. 6 is a partial end elevation thereof.

The invention is shown as applied to a drop bottom mine car adapted for the conveying of coal or other loose ladingfrom a receiving point to a pit or other point of discharge. The mine car is shown generally of the type set forth, for instance, in my prior patent, No. 2,001,471, granted May 14, 1935, representing a'four-wheel mine car having three drop bottom doors, adapted to travel on a'track formed by a pair of'rails designated generally R.

The general structure of the car comprises side and end structures l and. 2, respectively, the side wall structures l rising from a pair of oppositely disposed side sills 3 connected together at the ends of'the car by means of combined end sills and bumpers designated generally 4. The side and end sills 3 and 4 constitute the frame structure of the car for supporting the lading body of the car. The flaring side walls I rise upward at acute angles to the horizontal from the upper edges of the side sills 3.

The car is supported on wheels 5 and axles 5 connected with the side sills 3 by axle boxes i (Fig. 3). The flaring sides i of the body are cut away to receive the wheels, which are deeply inserted therein beneath wheel hood coverings 8. Opposite hood coverings 8 are connected together by means of a combined tie plate and shroud 9 which extends over the adjacent axle 6. Wheel hubs 5' cover the ends of the axles The car is shown as of the character provided with three drop bottom doors adapted for discharge in 1-2-3 order from front to rear of the car, which doors are designated respectively III, II and I2. Although any desired door structure may be used, the forward door i0 is shown as pivotally supported on a hinge rod l3, while each of the middle and rear doors I I and I2 is slidably and pivotally mounted on a hinge rod Mqextending between opposed boxes 1, with the extreme forward edge of said door projecting laterally from the hinge rod and arranged to support the free edge of the next forward door.

Thus upon release of the rear door it may drop suflicient to drag and move bodily rearward, thereby releasing the free edge of the middle door which will likewise move downward and rearward releasing the free edge of the forward door. This occurs usually just before the car reaches the bin and permits dropping of the forward door for discharge of the lading as soon as room enough is provided in the bin therebeneath, the other doors dropping in succession during forward movement of the car over the bin, in 1-23 order from front to rear of the car.

After dumping in passing over the bin, the doors are adapted to be closed by the usual doorclosing rails located in the track, said doors having indentations to ride thereon, which successively swing them into their closed positions. The doors may be pushed forward into tightly engaged supporting positions by wedge blocks l6 having upwardly and forwardly inclined front faces in position for engagement by the free edge of the rearward door I2, as set forth more fully in my prior United States Patent No. 2,001,471, granted May 14, 1935.

As shown in Figs. 1 to 4., provision is made for latching the free edge of the rearward door 82 for thereby holding the doors 10, H and I2 in their closed positions, retaining the lading in the car until the latching means is released for dumping. For this purpose latches l8 are provided adjacent the rear end of the car, spaced transversely on opposite sides of the center of the car, and pivotally supported by a shaft l9, extending transversely thereof on which said latches are fixed for swinging movement.

Each of the latches has a concave seat formed therein in position to engage the latch hook l1 attached to the free edge of the rearward door l2 to support said rearward door in closed position. As shown in Fig. 3, the seat it is located on the opposite side of the vertical plane passing through the axis of the shaft 19 from the door I 2, so that the weight of the door and the lading thereon tends to maintain the latched relation without any tendency for this weight to push the latch to one side. This is particularly true because of the concave shape of the seat 20 engaged by the convex end of the trunnion l1, whereby any movement of the latch tending to release the door must first raise up the free edge of the door.

The shaft i9 is journaled in brackets 2| fixed to the end structure of the car, and is so disposed relative to the adjacent end sill 4 as to locate the latches l8 forwardly of the rear end sill. The latches is are of a size such that their lower end portions do not project below the lower edge of the adjacent end sill and are disposed within the space between the rear door [2 and the rear end sill 4 in protected positions. This prevents disarrangement of the latches or accidental injury thereto in the event of wreckage of the car, as occurs frequently in mine operation, thus inlsuring adequate protection of the latches to maintain them in proper operating positions. The latches l8 and their supporting shaft l9 are protected from the lading in the car by a guard or reflecting plate 22 that extends thereover and is fixed to the car end wall structure 2. The plate 22 is rigidly fixed by rivets or welding to the end wall structure.

Provision is made for supporting each latch 18 in its door engaging position, for which purpose I have provided a coiled spring 23 interposed between a bracket shelf 24 and a side flange 25 projecting laterally from the latch I8 adjacent the upper end thereof.

Each of the latches has a lateral pin 26 attached thereto and projecting through a slot 21 in the adjacent portion of the end sill structure 4. The pin 26 normally seats on the lower end of the slot 21 to limit theforward swinging movement of the latch H3.

The latch supporting shaft l9 projects laterally through the flaring side wall of the car, but terminates at a point spaced inwardly from the vertical plane of the adjacent flaring side wall at the point where it extends out farther laterally. The projecting end of the shaft I9 is supported in a hanger bracket 28 suspended from the flaring side wall I. The extreme end of the shaft [9, externally of the bracket 28, is preferably square or of other polygonal shape, as at 29, to receive a monkey wrench, socket wrench, or other means of turning the shaft manually to release the latches and thus dump the lading even when the car is in a stationary position. 7

While the shaft I9 is protected by the flaring side wall of the car, further protection is afforded against damage from obstructions in the mine or elsewhere, by locating the shaft in protected position between projecting portions of the opposite car ends or end-sill structures. Each car end structure has a laterally projecting plate 30 extending outwardly beyond the end of the shaft I9, as shown in Fig. 4, and normally below the latch actuating means mounted thereon. The plate 30 has a notch 3| in the path of the tripping mechanism mounted at the track to permit access of the tripping mechanism to the latch actuating means mounted on the shaft l9.

In the form shown in Figs. 1 to 4, the tripping mechanism includes a cam member 32 keyed to the shaft I9, and normally so mounted as to be disposed substantially in the position shown in Fig. 2. The cam 32 has a forward sloping face 33 terminating in an offset shoulder 34 in position to receive the tripping shoe that actuates the cam.

The tripping shoe is shown at 35 and is slidably mounted in a socket 36 (see Fig. 2) in the upper end of an upstandingsupport 31. The support 3'! is'journaled. at. 3,8 in abracket 39; mounted in. a fixed positionin the track; A- coiled spring, 40 is sleeved into the shoe 35 and interposedbetween the. latter andthe bottom of the socketziifi, normallytending to hold. the. shoe in its.v elevated position; relative to the pivoted-support 31, but yielding to downward-pressure upon the upper end; ofthe shoe when: the: latter engages the sloping face 33;of the. tripping.cam.32, until the shoe is. pushed downward to the point where it engagestheshoulder 3,4, as shown in Fig. 2. The upper. end portion ofthe shoe 35 is substantially wedge-shaped to. facilitate actuation upon. engagement of the cam; The angle of engagement of the shoe 35-with theshoulder 3.4 of the cam 32.-is such that thereis no tendency for the cam to push the. shoe. further downuntil the shaft 19 has been-rotated sufficiently to release the latch mechanism. I

The extending actionof the shoe 3,5 is limited by a bolt 40. extending loosely; through bracket arms M- on thesupport 31;.andshoe 35, so as to prevent the shoe from rising too high, This boltmaybe so adjusted thatthe shoe 35 will nor-. mally engage only the shoulder 34. However, if the end of the car should, drop, the shoe then would-engage theface 33..which is shaped to depress the shoe into'engagement with the shoulder 3 4 to rotate the cam.

Theopposite side-of the'support 31 has an outwardly extending arm 42 from which is suspended a counterweight fliin the'form shown, although any suitable meansmay-be used to apply pressure in; a similar manner to the support 3'! to hold it in upstanding position. The arm 42 also limits the; forward swinging, movement of the support B'Tby engagingthe upper edge of the bracket 39, thus insuring. that the support will remain in upstanding position. If it be, desired to pass the car over a discharge bin without unlatching the door, this can bedone by swinging the s pport 37 by, hand to, a lowered position and holding it there with the shoe-35-,out of tripping position so that it cannot engagethe cam. 32.

Likewise, if the car shouldpass over the tripping v devicein a reverse direction, the cam 32-would cause swinging-movementofthe upstanding support. 3.1 against the resistance of the counterweight 43, until the. shoe .35 clears the cam, when the car. would merely pass over. without injury to theamechanism.

When the car movesaforward on the track, the tripping devicemountedtat'the track would be in such. position relative to: the point of. dumping as to dischargethe. lading at. the bin. The shoe 35" would normally project in such position that it would strike the sloping"v face 33 f. the cam 32. andmove downward along said sloping face until itoomes into engagement with the shoulder 3d onthe cam. In Fig. 2-of the drawings, the shoe 35 is about to: push back-the cam 32 to its door releasing. position and permit the reardoor 82" to drop and'discharge. thelading. The forward motion of-the car relative to the upstanding shoe 35'will'cause. the turning movement of the cam and thelatches l8' mounted on the shaft l9, thereby releasing. thefree edgeof the rearward door. The latches and-cam willthen be turned to. their initial positions by the coiled springs 23;. where the latches will again be in position to support the free edge of the door when the rearward doorismoved to a closed-position by the usual closing device mounted in thetrackway.

.The-latchactuating mechanism on'the car is thus disposed outside thetrack rails, but is in a protected position not only because it is housed beneath the flaring side wall of the car, but is also disposed between the laterally projecting plates 30 forming parts of: the end structures at opposite ends of the car. This affords protection for the latch actuating means against injury thereto, preventing such actuating meansfrom striking lumps of coal or other objects in the mine either during the operation of the car. or in the event of derailment.

In the form shownin Figs. 5 and 6, the latch structure on the car is similar to that described above, having one or more latches 68 supported by being fixed on a cross shaft 49 journaled in brackets secured to the end structure of the car. The shaft :29 projects through the sloping side wall 5 a of the car, but terminates inwardly of the vertical plane of the adjacent flaring side wall at the point where it extends out farther laterally, as shown in Fig. 6. A tripping cam or arm 52 is keyed on the projecting outer end of the shaft Q9 and has a sloping contact face 53 at the forward lower end thereof in. position for engagement by the tripping member.

In this form, the tripping member is designated at 55 and is mounted for vertical sliding movement within a guideway 56, from a retracted posi tion shown in full lines in Fig. 5 to an extended actuated position shown in dotted lines therein. The guideway 56 is secured to a casting 5? carried by a base member 58 extending transversely beneath the track rails R.

The lower end of the tripping member 55 is pivoted at 59 to the adjacent ends of connecting bars $9 which extend transversely of the track and are mounted for upward movement, either swinging or sliding relative to the guideway 55. The bars 50 project through a slot 6! in the guideway 55, at the inner side thereof and have their upward movement limited by engagement with the upper end of the slot. Fillers E52 are shown as secured to the upper edges of the bars 693 and projecting into the slot 6! to regulate the upward travel of the tripping member 55.

The bars 60 are operated by a solenoid coil 63 mounted on the transverse base member 5% at a suitable point in the track, The solenoid 53 has a, plunger at extending therefrom and pivotally connected at 65 with the bars 60, to actuate the bars to move the tripping member 55 upward to its tripping position.

The solenoid 63 should be actuated by a switch operated by the car when it reaches its dumping position. Several forms of such switches are shown in my prior application on Latch tripping mechanism, Ser. No. 473,013, filed January 20, 1943, one of which may be used here, actuated either from a projection on the side sill or by means of a wheel or other part of the car which closes the circuit at the proper time to energize the solenoid $3 for dumping the lading. When the solenoid is energized, it pulls upward on its plunger M which raises the cross bars fill, thereby moving the tripping member 55 upward in the guide its until the bars themselves or the fillers 67., engage the upper end of the slot 6!. At this time, the tripping member 55will be in its ele vated position as shown in dotted lines in Fig. 5, in the path of the cam member 52. When the cam member 52 strikes the tripping member 55, the latter will swing about the axis of the shaft 59 to a position where it will pass over'the tripping member. This swinging movement in a counter-clockwise direction in Fig. 5 will swing the-latches 48 out of supporting engagement with the free edge of the rearward door, thus releasing the doors for dropping, as described above.

The cam member 52 is protected by the end sill structure, which in this instance projects laterally of the car beyond the end of the shaft 49, as shown at 74 in Fig. 6. The lower end of the cam member 52 is located entirely above the lower edge of the end sill structure M, in protected. position thereby.

The tilting of the contact device by the car is such that the solenoid 63 will be deenergized so as to allow the tripping member 55 to drop to its lowered position before the end sill structure 14 at the rear reaches the member 55. A similar end sill structure at the front of the car would prevent any obstructions in the track from contact ing the tripping cam 52. It will be noted that the tripping cam 52 does not extend further downward than the lower ends of the latches 48 when in latched position so that both the latches and the tripping cam are protected by being located above the lower edges of the opposite end sill structures.

Where two latches are used on opposite sides of the center of the car for supporting the free edge of a single door, these may be actuated independently by being mounted on separate but aligned shafts 49, and locating a tripping device on each opposite side of the car, both actuated by a single solenoid 63. In that event, the bars 60 would project to opposite sides of the track and operate tripping devices at both ends thereof.

I claim:

1. In a drop bottom mine car adapted to be mounted on track rails and having side-sill means with transverse forward and rearward end-sill structures connected therewith and cooperating to form a load supporting frame, side wall structures extending upwardly from the side-sill means, a drop bottom door hinged to the frame structure about an axis extending transversely of the dumping conveyance, a latch for supporting the free edge portion of the door when closed, said latch having its lowest portion when in door supporting position above the portion of the lower edge of the adjacent end-sill structure lying in the same longitudinal upright plane, a shaft extending transversely of the car and supporting the latch rigidly fixed thereon for swinging movement in a direction lengthwise of the car upon rotation of the shaft to release the door for dropping, said shaft having an end portion projecting externally of the side-sill means and side wall at one end thereof and having actuating means on said projecting end portion, the end-sill structures having portions thereof projecting laterally of the car throughout the length of said projecting end portion of the shaft and disposed with the lower edge thereof below the shaft and said end-sill structure having a recess in the projecting lower edge portion thereof in the same longitudinal vertical plane as the actuating means.

2. In a dumping conveyance adapted to be mounted on a trackway and having a frame structure with transverse end portions, a drop bottom door mounted on the frame structure for down-- ward swinging movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft supporting the latch means, said shaft extending transversely of the conveyance and having an end portion thereof projecting externally of the frame structure, and a cam mounted on the projecting portion of the shaft, said cam having a forwardly inclined face and an offset shoulder at the lower 8 edgeportion of said face in'position to be engaged by a tripping device to actuate the shaft and latch means.

3. In conveying mechanism including a dumping conveyance mounted on a trackway and having a frame structure with opposite side walls projecting in an outward direction from said frame structure, a drop bottom door mounted for downward swinging movement relative to the frame structure, latch means for holding the door closed and movable to release "said door for dropping, a shaft connected with the latch means for moving said latch means to release the door, said shaft extending transversely of the conveyance with an end portion thereof projecting externally of the frame structure to a point beneath the outwardly extending portion of the adjacent side wall, a cam mounted on the projecting portion of the shaft, said cam having a forwardly inclined face and an offset shoulder at the'lower edge portion of said face, and means mounted at the trackway in position for cooperating engagement with the shoulder upon movement of the conveyance to a predetermined position on the trackway for rotating said shaft to cause the latch means to move to door-releasin position.

4. In conveying mechanism including a dumping conveyance mounted on a trackway and having a frame structure with transverse end portions and upwardly extending side wall portions projecting outwardly in opposite directions from the frame structure, a drop bottom door mounted in the frame structure for downward swinging movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft supporting the latch means and connected therewith for actuating the latch means upon rotation of the shaft, said shaft extending transversely of the conveyance and having an end portionthereof projecting externally of the frame structure and with said projecting end underlying the adjacent outwardly extending side wall portion, actuating means mounted on said projecting end portion of the shaft, the conveyance having a portion thereof extending transversely of the conveyance throughout at least a portion of said projecting end portion of the shaft to a point beyond the actuating means and with said shaft and actuating means disposed substantially above the lower edge of the projecting conveyance portion, said projecting portion having a relatively narrow notch in the lower edge thereof approximately corresponding in width with the actuating means, and means mounted at the trackway in position to pass through the notch for cooperating engagement with the actuating means upon movement of the conveyance to a predetermined position on the trackway to rotate the shaft for moving the latch means to release the door.

5. In conveying mechanism including a dumping conveyance mounted on a trackway and having a frame structure with transverse end portions and upwardly extending side wall portions projecting outwardly in opposite directions from the frame structure, a drop bottom door mounted in the frame structure for downward swinging movement relative thereto about an axis extending transversely of the conveyance,.latch means for holding the door closed and movable to release said door for dropping, a shaft supporting the latch means and rigidly fixed thereto and rotatable to move the latch means to release the door, said shaft extending transversely of the 9 conveyance and having an "end "portion thereof projectin externally of the "frame structure and withsaid projecting fend underlying'the adjacent outwardly extending side wall portion, actuating means mounted on said projecting end portion of the shaft, the adjacent frame end portion having a portion thereof projecting transversely of "the conveyance throughout a substantial portion of the length "of the projecting end portion of :the shaft and with said shaft and actuating means disposed substantially above the lower edge of said projecting end frame portion, and an abutment mounted at the trackway in position for cooper ating engagement with the actuating means upon movement oflthe conveyance to a predetermined position on'the trackway to rotate the shaft and latch means to release the door, said projecting end portion having a notch in the loweredge thereof of a width to receive the abutment and to prevent the entry' of appreciably wider articles. ,7 x @j 6. In conveying mechanism including a dump ing conveyance mounted on a trackway and having a frame structure with transverse end portions and upwardly extending side walljportions projecting outwardly in opposite directions from the frame structure, a drop bottom door mounted in the frame structure for downward swinging movement relative-thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft connected with the latch means, said shaft extendin transversely of the conveyance and having an end portion thereof projecting externally of the frame structure and with said projecting end underlying the adjacent outwardly extending side wall portion, a cam member mounted on the projecting end portion of the shaft, means connected with the frame structure and extending laterally substantially throughout the length of the projecting end portion of the shaft substantially below said shaft, a tripping shoe mounted at the trackway in position for engaging the cam member to move the shaft and latch means, and means movably supporting the tripping shoe on the trackway, said extending means having a notch in the lower portion thereof of a Width to receive the tripping shoe therethrough for actuation of the cam member and to prevent the entry thereto of appreciably wider articles.

'7. In conveying mechanism including a dumping conveyance mounted on a trackway and having a frame structure with transverse end portions, a drop bottom door mounted in the frame structure for downward swinging movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft supporting the latch means, said shaft extending transversely of the conveyance and having an end portion thereof projecting externally of the frame structure, a cam mounted on the projecting portion of the shaft, said cam having a forwardly inclined face and an offset shoulder at the lower edge portion of said face, a tripping shoe in position to engage said face, and means yieldingly supporting the shoe at the trackway for depressing movement thereof by the face into engagement with the shoulder to actuate the shaft and latch means.

8. In conveying mechanism including adumping conveyance mounted on a trackway and having a frame structure with transverse end portions, a drop bottom door mounted in the frame structure for downward swinging movement'r'elae tive thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft supporting the latch means, said shaft extending transversely of the conveyance and having an end portion thereof projecting externally of the frame structure, a cam mounted on the projecting portion of the shaft, said cam having a forwardly inclined face and an offset shoulder at the lower edge portion of said face, a tripping shoe in position to engage said face, and means yieldingly supporting the shoe on the trackway for depressing movement thereof by the face into engagement with the shoulder to actuate the shaft andlatch means, said supporting means including an upstanding support carrying the shoe, and means pivotally mounting the support on the 'trackway for bodily swinging movement of the shoe out of the path of the cam.

9. In conveying mechanism including a dumping conveyance, mounted on a trackwayand having a frame structure with transverse end portions, a drop bottom door mounted in the frame structure for downward swinging movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft connected with the latch means and extending transversely of the conveyance and having an end portion thereof projecting externally of at least a portion of the frame structure, an operating member mounted on the projecting end portion of the shaft, one of the transverse end portions extending substantially throughout the length of said projecting end portion of the shaft with said shaft and operating member disposed substantially above the lower edge of said extended transverse end portion, said transverse end portion having a recess in the lower edge thereof arranged substantially in longitudinal alignment with the operating member in position for engagement of said operating member by tripping means mounted in the trackway.

10. In conveying mechanism including a dumping conveyance mounted on a trackway and having a frame structure with transverse end portions, a drop bottom door 'mounted in the frame structure for downward swinging movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft connected with the latch means and extending transversely of the conveyance and having an end portion thereof projecting externally of at least a portion of the frame structure, an operating member mounted on the projecting end portion of the shaft, one of the transverse end portions extending substantially throughout the length of said projecting end portion of the shaft with said shaft and operating member disposed substantially above the lower edge of said extended transverse end portion, said transverse end portion having a notch in the lower edge thereof in longitudinal alignment with the operating member, and tripping means mounted at the trackway in position for relatively moving through said notch and to engage the operating member to turn the shaft and release the latch means.

11. In a dumping conveyance having a frame structure with transverse end portions, a drop bottom door mounted in the frame structure for downward swinging movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft connected with the latch means and extending transversely of the conveyance and having an end portion thereof projecting externally of at least a portion of the frame structure, an operating member mountedon the projecting end portion of the shaft, transverse means on the conveyance forwardly of the shaft and extending substantially throughout the length of said projecting end portion of the shaft with said shaft and operating member disposed approximately above the lower edge of said extended transverse means, said transverse means having a recess in the lower edge thereof arranged substantially in longitudinal alignment with the operating member in position for engagement of said operating member by tripping means mounted in the trackway.

12. In a dumping conveyance having a frame structure with transverse end portions, a drop bottom door mounted in the frame structure for downward swinging, movement relative thereto about an axis extending transversely of the conveyance, latch means for holding the door closed and movable to release said door for dropping, a shaft connected with the latch means and extending transversely of the conveyance and having an end portion thereof projecting externally 12 of at least a portion of the frame structure, an operating member mounted on the projecting end portion of the shaft, an upright transverse plate on the conveyance forwardly of the shaft and extending substantially throughout the length of said projecting end portion of the shaft with said shaft and operating member disposed approximately above the lower edge of said extended transverse plate, said transverse plate having a recess in the lower edge thereof arranged substantially in longitudinal alignment with the operating member in position for engagement of said operating member by tripping means mounted in the trackway and passing through the notch in tripping position.

HUGH W. SANFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Smith Jan. 9, 1940 

